Many manufacturers of electronic devices are now turning away manual insertion of components into circuit boards and, instead, are relying on automated insertion techniques in an effort to reduce labor costs and fabrication time. To this end, machines have been especially developed for automatically inserting components into circuit boards. Examples of an automated component insertion machine are found in U.S. Pat. Nos. 4,030,180 to M. V. Pierson, 4,283,836 to S. Janisiewicz et al. and 4,367,584 to S. Janisiewicz et al.
While present day automated component insertion machines are capable of inserting components having rigid, dual in-line leads, problems often arise in attempting to utilize such machines to insert components having very flexible dual in-line leads, particularly components having as many as 20 flexible leads on each side thereof. Flexible leads are often provided on the component to substantially absorb the shock imparted thereto when the circuit board to which the component is mounted is flexed.
One reason why components having flexible leads are difficult to insert is because of the inability of present day insertion machines to align each of the many leads with corresponding apertures in the circuit board. If the flexible leads depending from the component are sufficiently misaligned with the corresponding apertures, then the leads are likely to bend as they contact the circuit board for insertion therein. The greater the flexibility of the lead on the component, the more likely the lead will bend when misaligned with the corresponding aperture in the board. Further, the greater the lead flexibility, the more likely the leads will become bent during normal handling of the part prior to insertion.
Should the leads of the component become sufficiently bent so as to preclude insertion into the circuit board, then the component may have to be reworked or even discarded. Reworking the component to straighten the leads thereof is time consuming and delays the insertion process. Discarding a component, once the leads have become sufficiently bent to preclude the straightening thereof, can prove expensive especially if the component is costly.
A greater problem may result if a component having bent leads is actually inserted and then the leads are then soldered to the board. Should one or more leads of the component not be received in the proper aperture in the board by virtue of having become bent then the circuit board will not operate properly. Detection and correction of such faults is a very expensive and difficult procedure.
In an effort to overcome the problem of lead misalignment, U.S. Pat. No. 3,442,430 issued May 6, 1969 to D. W. Ackerman et al. discloses a component insertion machine which utilizes slotted combs for guiding the leads into the apertures in the board. Each of the combs of Ackerman et al. is located on the tip of each of a pair of spaced apart inwardly tapered, resilient fingers. The fingers are located on opposite sides of a reciprocatable insertion ram having a component carrying head mounted to its bottom end. As the insertion ram is driven downwardly to insert a component carried by the head, the leads on the component are received in slots in the combs and are guided thereby into the corresponding apertures in the circuit board.
Like other prior art component insertion machines, the Ackerman et al. machine may incur difficulties in inserting components having very flexible leads. If the leads of the component are somewhat bent, then, as the insertion ram is driven downwardly, the leads of the component may catch on the combs before entering the slots therein. As a result, further lead bending may occur, which may prevent component insertion.
The foregoing problems associated with the insertion of components having flexible dual in-line depending leads are particularly severe with hybrid integrated circuits. Hybrid integrated circuits (HIC's) are electronic components comprised of a component-carrying ceramic substrate having a plurality of very flexible leads depending from opposite sides thereof. Some hybrid integrated circuits have as many as 100 leads depending from each side of the substrate which makes alignment of each of the leads thereof with the corresponding apertures in the circuit board extremely difficult. Moreover, the leads of the HIC are so flexible that after they are soldered into the apertures of the circuit board, the force required to pull them out during desoldering to correct for a misinserted HIC will cause sufficient bending of the leads as to preclude reworking thereof. Since present day HIC's are expensive, it is desirable to insert the leads properly.
Accordingly, there is a need for a technique for inserting the flexible leads of a hybrid integrated circuit into corresponding apertures on a printed circuit board without bending.